This application claims priority from pending Swedish Patent Application Numbers 0002058-6 filed on May 31, 2000 and 0002943-9 filed on Aug. 18, 2000.
The present invention concerns a caliper for a disc brake and a method for assembly of a brake mechanism in said caliper.
The caliper and brake mechanism according to the present invention is primarily intended for a heavy road vehicle but may quite as well be used for a lighter road vehicle or a rail vehicle.
It is previously known to furnish a brake caliper having a cover attached from the outside. See e.g. WO 96/12 900. The brake mechanism is held together as a unit during assembly. In this type of caliper there were problems concerning the sealing of the cover etc.
To improve the above concept a closed caliper was developed in which the brake unit is mounted from the other side as compared to the above caliper having a cover. See e.g. DE,C,195 15 063. This solution may give difficulties concerning strength of the bearing cages, assembly of the brake mechanism and machining of the caliper.
In the above and similar calipers the machining is made from the side closest to the brake disc, normally referred to as the front side. This is often cumbersome and time consuming and thus rather expensive, as there is a rather long distance for the tool. It is also previously known to machine support surfaces for the lever of the brake mechanism, through holes in the flanks of the caliper. Thus, there is a need for a method of machining the inside of the caliper, which is less time consuming and less expensive.
The assembly of the brake mechanism in the caliper is often cumbersome due to a tight tolerance between the size of the brake mechanism and the caliper. Due to the tight tolerance the time for assembly is rather long. Thus, there is a need for a method of assembly, which will reduce the difficulties and the time it takes to assemble the brake mechanism inside the caliper.
The side of the caliper facing the brake disc is normally referred to as the front side. The opposite side of the caliper is referred to as the rear side. When these and similar expressions are used in this description in connection with the caliper they refer to the said respective sides.
One object of the present invention is to facilitate machining of the inside of the caliper.
In order to prepare the caliper for the assembly of the brake mechanism, the inside of the caliper is normally machined. According to the invention the machining is preferably made through an opening of the caliper. The opening is placed on the rear side of the caliper. Thus, the caliper will have an open design and is in this description often referred to as an open caliper. In order to give the bearing bracket of the brake mechanism correct and accurate position the caliper has to be machined from the rear. It is difficult and time consuming to machine the caliper from the inside as it will demand the use of an angular cutter and an extensive fixture which is not feasible in line production.
A further object of the present invention is to facilitate assembly of the brake mechanism inside the caliper.
The invention makes it possible to assemble the brake mechanism without the use of fastening means between the brake mechanism and the rear of the caliper. This is of advantage as the reaction forces on the fastening means will be considerable at a high braking torque. The brake mechanism is held in position by means of a spring urging the mechanism against the caliper.
Assembly is made considerably easier as it is possible to xe2x80x9coperatexe2x80x9d from two directions as the bearing bracket and the sealing together with the further modules of the mechanism are brought into the caliper. It is then also possible to keep the bearing bracket fixed from the outside until the other modules and the mechanism spring has been mounted. The bearing bracket may be made in any optional and suitable material.
The brake mechanism may be assembled as one unit in the caliper. However, due to the dimensions of the caliper and/or the brake mechanism it may be necessary to assemble the brake mechanism in two or more parts. It may not be physically possible to insert the brake mechanism as one unit.
Further objects and advantages of the invention will be obvious for a person skilled in the art from reading the description below.
The brake mechanism of the present invention is preferably pneumatically actuated, but it may also be hydraulically or electrically actuated.